Antimicrobial water soluble substrates

ABSTRACT

An antimicrobial water soluble substrate is formed by combining a silane, generically a quaternary ammonium salt form of a silane, with a water soluble powder selected from the group consisting of antiperspirant salts, starches, clays, and sugars. When the substrate is dissolved in water, the silane is released for redeposition.

BACKGROUND OF THE INVENTION

This invention relates to antimicrobial agents and more particularly tonew water soluble substrates including quaternary ammonium saltcompounds having biological activity.

Antimicrobial agents are chemical compositions that are used to preventmicrobiological contamination and deterioration of products, materials,and systems. Particular areas of application of antimicrobial agents andcompositions are, for example, cosmetics, disinfectants, sanitizers,wood preservation, food, animal feed, cooling water, metalworkingfluids, hospital and medical uses, plastics and resins, petroleum, pumpand paper, textiles, latex, adhesives, leather and hides, and paintslurries. Of the diverse categories of antimicrobial agents andcompositions, quaternary ammonium compounds represent one of the largestof the classes of antimicrobial agents in use. At low concentrations,quaternary ammonium type antimicrobial agents are bacteriostatic,fungistatic, algistatic, sporostatic, and tuberculostatic. At mediumconcentrations they are bactericidal, fungicidal, algicidal, andviricidal against lipophilic viruses. Silicone quaternary ammonium saltcompounds are well known as exemplified by U.S. Pat. No. 3,560,385,issued Feb. 2, 1971, and the use of such compounds as antimicrobialagents is taught, for example, in a wide variety of patents such as U.S.Pat. No. 3,730,701, issued May 1, 1973, and U.S. Pat. No. 3,817,739issued June 18, 1974, where the compounds are used to inhibit algae,U.S. Pat. No. 3,794,736, issued Feb. 26, 1974, and U.S. Pat. No.3,860,709, issued Jan. 14, 1975, where they are employed for sterilizingor disinfecting a variety of surfaces and instruments; U.S. Pat. No.3,865,728, issued Feb. 11, 1975, where the compounds are used to treataquarium filters; U.S. Pat. No. 4,259,103, issued Mar.31, 1981; and inBritish Patent No. 1,386,876, of Mar. 12, 1975. Published unexaminedEuropean Application No. 228464 of July 15, 1987, teaches thatmicroorganisms on plants can be killed by the application thereto of anaqueous mixture of a surfactant and an organosilicon quaternary ammoniumcompound. In a particular application of an antimicrobial siliconequaternary ammonium compound, a paper substrate is rendered resistant tothe growth of microorganisms in U.S. Pat. No. 4,282,366, issued Aug. 4,1981. In U.S. Pat. No. 4,504,541, issued Mar. 12, 1985, an antimicrobialfabric is disclosed which is resistant to discoloration and yellowing bytreatment of the fabric with a quaternary ammonium base containing anorganosilicone. U.S. Pat. No. 4,615,937, issued Oct. 7, 1986, as well asits companion U.S. Pat. No. 4,692,374, issued Sept. 8, 1987, relate towet wiper towelettes having an antimicrobial agent substantive to thefibers of the web and being an organosilicon quaternary ammoniumcompound. In a series of Burlington Industries, Inc. U.S. Pat. No.4,408,996, issued Oct. 11, 1983, U.S. Pat. No. 4,414,268, issued Nov. 8,1983, U.S. Pat. No. 4,425,372, issued Jan. 10, 1984, and U.S. Pat. No.4,395,454, issued July 26, 1983, such compounds are disclosed to beuseful in surgical drapes, dressings, and bandages. This same assigneealso discloses these compounds as being employed in surgeon's gowns inU.S. Pat. No. 4,411,928, issued Oct. 25, 1983, and U.S. Pat. No.4,467,013, issued Aug. 21, 1984. Organosilicon quaternary ammoniumcompounds have been employed in carpets, in U.S. Pat. No. 4,371,577,issued Feb. 1, 1983; applied to walls, added to paints, and sprayed intoshoes, in U.S. Pat. No. 4,394,378, issued July 19, 1983; applied topolyethylene surfaces and used in pillow ticking in U.S. Pat. No.4,721,511, issued Jan. 26, 1988; in flexible polyurethane foams offine-celled, soft, resilient articles of manufacture in U.S. Pat. No.4,631,297, issued Dec. 23, 1986; and mixed with a surfactant in JapaneseKokai Application No. 58,156809, filed Aug. 26, 1983, of Sanyo ChemicalIndustries, Ltd., for the purpose of achieving uniformity ofdistribution of the compounds to a surface. Thus, the versatility ofsuch compositions is readily apparent. However, no one, as far as isknown, has disclosed an organosilicon quaternary ammonium compoundattached to a water soluble substrate in accordance with the presentinvention and having utility as antimicrobially effective agents. Thenew compositions of the present invention act in preventingmicrobiological contamination and deterioration, and the new andheretofore undisclosed novel compositions set forth in the presentinvention possess unique features and advantages over existingantimicrobial treating agents. Thus, the compounds of the presentinvention may be dissolved in water whereupon the silane responsible forthe microbiological activity is released from the water solublesubstrate to which it was initially adhered, and is free to adhere tothe next available substrate to which the solution is applied or tosurfaces immersed therein.

SUMMARY OF THE INVENTION

This invention relates to an antimicrobial water soluble substrate or asubstrate formed by a colloidal suspension produced by combining asilane, generically a quaternary ammonium salt form of a silane, with awater soluble powder selected from the group consisting ofantiperspirant salts, starches, clays, and sugars. When the substrate isdissolved in water, the silane is released for redeposition. Thus, thetreated powders in accordance with the present invention can bedissolved in water, and the solution applied to a substrate where thesilane is redeposited from the powder to the substrate. Alternatively,the powder may be sprinkled onto a moistened or wet surface where thesilane responsible for the microbiological activity will release fromthe powder and redeposit and adhere to the moistened or wet substrate towhich it has been sprinkled. Typical of water soluble powders are thecategory of antiperspirant-type salts and agents in powder form, forexample, aluminum chlorohydrate and aluminum-zirconiumtetrachlorohydrex-glycinate. Other materials which may be used includemethyl cellulose; hydroxy ethyl cellulose; sugar such as glucose,fructose, lactose, maltose, and especially sucrose, particularly finelypulverized sugar known as confectioners' sugar; magnesium aluminumsilicate; guar gum; colloidal silica; and colloidal clay. There may alsobe employed a substrate of a mixture of macro cellulose and sodiumcarboxy methyl cellulose. The treatment level of the silane can be from0.5 to 2.0 percent by weight based on the weight of the powder,preferably at levels greater than two percent.

It is therefore an object of the present invention to provide anantimicrobial agent that can be applied to substrates to produce anantimicrobial surface having broad spectrum efficacy. In contrast toprior art techniques which have been limited to the application of theagents from aqueous systems to non-water soluble substrates, the presentinvention involves treatment of water soluble substrates. Once thetreated water soluble substrates are dissolved or redissolved in water,the silane agent is released from the water soluble substrate to whichit had been adhered, typically a powder, and is available to attach andadhere to another substrate, such as a non-water soluble substrate,rendering it antimicrobial. The non-water soluble substrate could be,for example, a textile or the human underarm area of the skin.

These and other features, objects, and advantages, of the presentinvention will become apparent from the following detailed descriptionof the invention.

DETAILED DESCRIPTION OF THE INVENTION

Ammonium compounds in which all of the hydrogen atoms have beensubstituted by alkyl groups are called quaternary ammonium salts. Thesecompounds may be represented in a general sense by the formula: ##STR1##

The nitrogen atom includes four covalently bonded substituents thatprovide a cationic charge. The R groups can be any organic substituentthat provides for a carbon and nitrogen bond with similar and dissimilarR groups. The counterion X is typically halogen. Use of quaternaryammonium compounds is based on the lipophilic portion of the molecularwhich bears a positive charge. Since most surfaces are negativelycharged, solutions of these cationic surface active agents are readilyadsorbed to the negatively charged surface. This affinity for negativelycharged surfaces is exhibited by3-(trimethoxysilyl)propyldimethyloctadecyl ammonium chloride of theformula: ##STR2##

In the presence of moisture, this antimicrobial agent imparts a durable,wash resistant, broad spectrum biostatic surface antimicrobial finish toa substrate. The organosilicon quaternary ammonium compound is leachresistant, nonmigrating, and is not consumed by microorganisms. It iseffective against gram positive and gram negative bacteria, fungi algae,yeasts, mold, rot, mildew, and malodor. The silicone quaternary ammoniumsalt provides durable, bacteriostatic, fungistatic, and algistaticsurfaces. It can be applied to organic or inorganic surfaces as a diluteaqueous solution of 0.1-1.5 percent by weight of active ingredient.After the alkoxysilane is applied to a surface, it is chemically bondedto the substrate by condensation of the silanol groups at the surface.The compound is a low viscosity, light to dark amber liquid, soluble inwater, alcohols, ketones, esters, hydrocarbons, and chlorinatedhydrocarbons. The compound has been used in applications such as, forexample, socks, filtration media, bed sheets, blankets, bedspreads,carpet, draperies, fire hose fabric materials, humidifier belts,mattress pads, mattress ticking, underwear, nonwoven disposable diapers,nonwoven fabrics, outerwear fabrics, nylon hosiery, vinyl paper,wallpaper, polyurethane cushions, roofing materials, sand bags, tents,tarpaulins, sails, rope, athletic and casual shoes, shoe insoles, showercurtains, toilet tanks, toilet seat covers, throw rugs, towels,umbrellas, upholstery fiberfill, intimate apparel, wiping cloths, andmedical devices.

The compositions of the present invention were prepared in accordancewith Examples set forth hereinbelow, and in the Examples as well as inthe Tables, the composition identified as TMS refers to a productmanufactured by the Dow Corning Corporation, Midland, Michigan, as anantimicrobial agent and is 3-(trimethoxysilyl)-propyloctadecyldimethylammonium chloride diluted to forty-two percent active ingredients byweight with methanol.

The anion of an aqueous sodium salt of bromphenol blue can be complexedwith the cation of a polymerized silane of this invention while it is ona substrate. The blue colored complex, substantive to a water rinse, isqualitatively indicative of the presence of the cation on the substratethus indicating the extent of antimicrobial agent on a given substrate.A comparison of the intensity of retained blue color to a color standardis used as a check to determine if the treatment has been appliedproperly.

The method consists of preparing a 0.02 to 0.04 weight percent solutionof bromphenol blue in distilled water. This solution is made alkalineusing a few drops of saturated Na₂ CO₃ solution per 100 milliliters ofthe solution. Two to three drops of this solution are placed on thetreated substrate and allowed to stand for two minutes. The substrate isthen rinsed with copious amounts of tap water and the substrate isobserved for a blue stain and it is compared to a color standard.

For a spectrophotometric determination, the following test is used.

The sodium salt of bromphenol blue is depleted from a standard solutionby complexing with the cations on a treated substrate. The change inbromphenol blue concentration is determined spectrophotometrically or bycomparison with color standards whereby the level of substrate treatmentby the cationic silane is determinable.

The method consists of preparing a 0.02 weight percent standard solutionof bromphenol blue in distilled water. It is made alkaline with a fewdrops of saturated Na₂ CO₃ solution per 100 milliliters of bromphenolblue solution. The color of this solution is purple.

The blank solution is adjusted to yield a 10 to 12% transmittancereading when measured in 1 cm cells using a spectrophotometer set at 589nm by the following method.

Fill a container 3/4 full of distilled water and add 2 ml of the 0.02%standard bromphenol blue solution for every 50 ml of distilled water.Add 0.5 ml of a 1% Triton® X-100 surfactant (manufactured by Rohm andHaas, Philadelphia, PA, USA) aqueous solution for every 50 ml of water.Mix, and using the spectrophotometer, determine the maximum absorbance.Adjust the upper zero to 100% transmittance with distilled water. Checkthe percent transmittance of the working bromphenol blue solution at themaximum absorbance setting. Adjust the blank solution to 10 to 12%transmittance with either water or bromphenol blue standard solution asnecessary.

The samples of treated substrate are tested by placing 0.5 gram samplesof the substrate standards in a flask large enough for substantialagitation of the sample and the test solution. Add 50 ml of the workingsolution. Agitate for 20 minutes on a wrist-action shaker. Fill the testcurvette with the test solution. Centrifuge if particulate matter ispresent. Measure the % transmittance at the wavelength set forth above.The transmittance is compared against a standard curve prepared bypreparing several substrate samples of known concentration of thecationic silane. For example, samples containing a known amount ofcationic silane at, for example, 0%, 0.25%, 0.50%, 0.75% and 1% are readspectrophotometrically and a curve is plotted. The results of thismethod are reported below.

The silanes useful in this invention have the general formula ##STR3##It should be noted that generically, these materials are quaternaryammonium salts of silanes. Most of the silanes falling within the scopeof this invention are known silanes and references disclosing suchsilanes are numerous. One such reference, U.S. Pat. No. 4,259,103,issued to James R. Malek and John L. Speier, on Mar. 31, 1981, discussesthe use of such silanes to render the surfaces of certain substratesantimicrobial. Canadian Patent No. 1,010,782, issued to Charles A. Rothshows the use of fillers treated with certain silanes to be used inpaints and the like to give antimicrobial effects.

Numerous other publications have disclosed such silanes, namely, A. J.Isquith, E. A. Abbott and P. A. Walters, Applied Microbiology, December,1972, pages 859-863; P. A. Walters, E. A. Abbott and A. J. Isquith,Applied Microbiology, 25, No. 2, p. 253-256, February 1973 and E. A.Abbott and A. J. Isquith, U.S. Pat. No. 3,794,736 issued Feb. 26, 1974,U.S. Pat. No. 4,406,892, issued Sept. 27, 1983, among others.

For purposes of this invention, the silanes can be used neat or they canbe used in solvent or aqueous-solvent solutions. When the silanes areused neat, the inventive process is preferably carried out in a systemin which some small amount of water is present. If it is not possible tohave a system with some small amount of water present, then a watersoluble or water-dispersable, low molecular weight hydrolyzate of thesilane may be used. What is important is the fact that the durability ofany effect produced by the silane as part of a product requires that thesilane molecule react with a surface to a certain extent. The mostreactive species, as far as the silanes are concerned, is the .tbd.SiOHthat is formed by hydrolysis of the alkoxy groups present on the silane.The .tbd.SiOH groups tend to react with the surface and bind the silanesto the surface. It is believed by the inventor even through the primemode of coupling to the surface system is by the route described above,it is also believed by the inventor that the alkoxy groups on thesilicon atom may also participate in their own right to bind to thesurface.

Preferred for this invention is a reactive surface containing some smallamount of water. By "reactive", it is meant that the surface mustcontain some groups which will react with some of the silanols generatedby hydrolysis of the silanes of this invention.

R in the silanes of this invention are alkyl groups of 1 to 4 carbonatoms. Thus, useful as R in this invention are the methyl, ethyl, propyland butyl radicals. In the above formulas RO can also be R. R can alsobe hydrogen thus indicating the silanol form, i.e. the hydrolyzate. Thevalue of a is 0, 1 or 2 and R' is a methyl or ethyl radical.

R" for purposes of this invention is an alkylene group of 1 to 4 carbonatoms. Thus, R" can be alkylene groups such as methylene, ethylene,propylene, and butylene. R'", R"", and R^(v) are each independentlyselected from a group which consists of alkyl radicals of 1 to 18carbons --CH₂ C₆ H₅, --CH₂ CH₂ OH, --CH₂ OH, and --(CH₂)_(x)NHC(O)R^(vi). x has a value of from 2 to 10 and R^(vi) is aperfluoroalkyl radical having from 1 to 12 carbon atoms. X is chloride,bromide, fluoride, iodide, acetate or tosylate.

Preferred for this invention are the silanes of the general formula##STR4## R is methyl or ethyl; a has a value of zero; R" is propylene;R'" is methyl or ethyl; R"" and R^(v) are selected from alkyl groupscontaining 1 to 18 carbon atoms wherein at least one such group islarger than eight carbon atoms and x is either chloride, acetate ortosylate.

Most preferred for this invention are those silanes having the formula

    (CH.sub.3 O).sub.3 Si(CH.sub.2).sub.3 N⊕(CH.sub.3).sub.2 C.sub.18 H.sub.37 C1.sup.- and (CH.sub.3 O).sub.3 Si(CH.sub.2).sub.3 --N⊕CH.sub.3 (C.sub.10 H.sub.21).sub.2 C1.sup.-.

As indicated above, most of these silanes are known from the literatureand methods for their preparation are known as well. See, for example,U.S. Pat. No. 4,282,366, issued Aug. 4, 1981; U.S. Pat. No. 4,394,378,issued July 19, 1983, and U.S. Pat. No. 3,661,963 issued May 9, 1972,among others.

Specific silanes within the scope of the invention are represented bythe formulae: ##STR5## X is chlorine in the above structures.

EXAMPLE I

Into a flask containing twenty grams of solvent was added one milliliterof TMS, three milliliters of water, and three grams of Powder A(aluminumchlorohydrate). The contents of the flask were mixed and agitated at lowheat for twenty to thirty minutes, and filtered. The material was airdried to powder form. The power was rinsed in anhydrous isopropylalcohol in order to remove any excess or residual TMS. The rinsed powderwas again air dried and subjected to bromophenol blue analysis asoutlined previously.

EXAMPLE II

Into a flask containing twenty grams of solvent was added one milliliterof TMS, three milliliters of water, and three grams of PowderB(aluminum-zirconium tetrachlorohydrex-glycinate). The contents of theflask were mixed and agitated at low heat for twenty to thirty minutes,and filtered. The material was air dried to powder form. The power wasrinsed in anhydrous isopropyl alcohol in order to remove any excess orresidual TMS. The rinsed powder was again air dried and subjected tobromophenol blue analysis as outlined previously.

EXAMPLE III

Examples I and II were repeated for each solvent system shown in TableI. Thus, a series of sixteen systems were prepared and tested bybromophenol blue analysis; each of the eight solvents being prepared andtested with each one of powders A and B. The data are tabulated in TableI and the results of the bromophenol blue analysis is shown in Table Iunder the heading "TEST". All of the systems tested positive with theexception of the Powder A-solvent water system. High intensity wasmanifested by the systems of including the volatile cyclic emulsion, andthe solvents isopropanol and toluene with Powders A and B, respectively.Both Powders A and B are water soluble powder forms of antiperspirantagents. All of the powders prepared and tested in accordance with theforegoing procedures and as tabulated in Table I remained water solubleafter the preparation and testing procedure. The powders wereredissolved in water releasing the TMS, and textile materials immersedtherein were rendered antimicrobial by the redeposition of the TMSthereon. The powders were also sprinkled on carpets samples that hadbeen moistened with water and found to be antimicrobial after the carpetsamples had been dried and the powder removed by vacuuming, indicating arelease of the TMS from the powder and redeposition onto the carpetfiber.

                  TABLE I                                                         ______________________________________                                                                   Powder                                             Solvent (20 gm.)                                                                          TMS    Water   A      Powder B                                                                              Test                                ______________________________________                                        Water       1 ml.  3 ml.   3 gm.  --      -                                   Water       1 ml.  3 ml.   --     3 gm.   0                                   Methanol    1 ml.  3 ml.   3 gm.  --      +                                   Methanol    1 ml.  3 ml.   --     3 gm.   +                                   Isopropanol 1 ml.  3 ml.   3 gm.  --      +°                           Isopropanol 1 ml.  3 ml.   --     3 gm.   0                                   Acetone     1 ml.  3 ml.   3 gm.  --      +                                   Acetone     1 ml.  3 ml.   --     3 gm.   +                                   Toluene     1 ml.  3 ml.   3 gm.  --      +                                   Toluene     1 ml.  3 ml.   --     3 gm.   +°                           Hexane      1 ml.  3 ml.   3 gm.  --      +                                   Hexane      1 ml.  3 ml.   --     3 gm.   +                                   Volatile Cyclic                                                                           1 ml.  3 ml.   3 gm.  --      +°                           Emulsion    1 ml.  3 ml.   --     3 gm.   +°                           MeOH (No Water)                                                                           1 ml.  --      3 gm.  --      +                                   MeOH (No Water)                                                                           1 ml.  --      --     3 gm.   +                                   ______________________________________                                         Powder A = aluminum chlorohydrate                                             Powder B = Al--ZR chlorohydrexglycinate                                       Test - = powder remained white                                                Test 0 = slight blue color                                                    Test + = blue color                                                           Test +° = intenseuniform blue color                               

In Table I, the "volatile cyclic emulsion" is an emulsion where anantimicrobial agent comprised of3-(trimethoxysilyl)propyloctadecyldimethyl ammonium chloride and3-chloropropyltrimethoxysilane is the emulsifier, water is thecontinuous phase, and the discontinuous phase is a volatile silicone ofdecamethylcyclopentasiloxane.

The antimicrobial activity of a treated surface is evaluated by shakinga sample weighing 0.75 grams in a 750,000 to 1,500,000 count Klebsiellapneumoniae suspension for a one hour contact time. The suspension isserially diluted, both before and after contact, and cultured. Thenumber of viable organisms in the suspensions is determined. The percentreduction based on the original count is determined. The method isintended for those surfaces having a reduction capability of 75 to 100%for the specified contact time. The results are reported below as thepercent reduction.

Media used in this test are nutrient broth, catalog No. 0003-01-6 andtryptone glucose extract agar, catalog No. 0002-01-7 both available fromDifco Laboratories, Detroit, Mich., U.S.A. The microorganism used isKlebisiella pneumoniae American Type Culture Collection; Rockville, Md.U.S.A., catalog No. 4352.

The procedure used for determining the zero contact time counts iscarried out by utilizing two sterile 250 ml. screw-cap Erlenmeyer flasksfor each sample. To each flask is added 70 ml of sterile buffersolution. To each flask is added, aseptically, 5 ml of the organisminoculum. The flasks are capped and placed on a wrist action shaker.They are shaken at maximum speed for 1 minute. Each flask is consideredto be at zero contact time and is immediately subsampled by transferring1 ml of each solution to a separate test tube containing 9 ml of sterilebuffer. The tubes are agitated with a vortex mixer and then 1 ml of eachsolution is transferred to a second test tube containing 9 ml of sterilebuffer. Then, after agitation of the tubes, 1 ml of each tube istransferred to a separate sterile petri dish. Duplicates are alsoprepared. Sixteen ml of molten (42° C.) tryptone glucose extract agar isadded to each dish. The dishes are each rotated ten times clockwise andten times counterclockwise. The dishes are then incubated at 37° C. for24 to 36 hours. The colonies are counted considering only those between30 and 300 count as significant. Duplicate samples are averaged. Theprocedure used for determining the bacterial count after 1 hour isessentially the same as that used to determine the count at the zerocontact time. The only difference is that pour plating is performed atthe 10⁰ and 10⁻¹ dilutions as well as at the 10⁻² dilution. "Percentreduction" is calculated by the formula ##EQU1## where A is the countper milliliter for the flask containing the treated substrate; B is zerocontact time count per milliliter for the flask used to determine "A"before the addition of the treated substrate and C is zero contact timecount per milliliter for the untreated control substrate.

EXAMPLE IV

Twenty grams of confectioners' sugar was added to one hundredmilliliters of toluene, together with ten grams of TMS. The mixture wasstirred for one hour and the liquid was removed by filtration. Theparticulate was rinsed three times with toluene. The particulate wassubjected to bromophenol blue analysis as outlined above, and thepercent transmittance determined to be 66.0. The particulate was alsoevaluated for antimicrobial activity on fabric in accordance with theprocedure outlined above, and the percent reduction was determined to beone-hundred percent.

It will be apparent from the foregoing that many other variations andmodifications may be made in the structures, compounds, compositions,articles of manufacture, and methods described herein without departingsubstantially from the essential features and concepts of the presentinvention. Accordingly, it should be clearly understood that the formsof the invention described herein are exemplary only and are notintended as limitations on the scope of the present invention.

That which is claimed is:
 1. A composition comprising a water-solubleantiperspirant salt having chemically bonded thereto an organosilanehaving the general formula selected from the group consisting of##STR6## wherein, in each formula, R is an alkyl radical of 1 to 4carbon atoms or hydrogen;a has a value of 0, 1 or 2; R' is a methyl orethyl radical; R" is an alkylene group of 1 to 4 carbon atoms; R'", R""and R^(v) are each independently selected from a group consisting ofalkyl radicals of 1 to 18 carbon atoms, --CH₂ CH₆ H₅, --CH₂ CH₂ OH,--CH₂ Oh, and --(CH₂)_(x) NHC(O)R^(vi), wherein x has a value of from 2to 10 and R^(vi) is a perfluoroalkyl radical having from 1 to 12 carbonatoms; X is chloride, bromide, fluoride, iodide, acetate or tosylate,thesalt being aluminum chlorohydrate powder.
 2. A composition comprising awater-soluble antiperspirant salt having chemically bonded thereto anorganosilane having the general formula selected from the groupconsisting of ##STR7## wherein, in each formula, R is an alkyl radicalof 1 to 4 carbon atoms or hydrogen;a has a value of 0, 1 or 2; R' is amethyl or ethyl radical; R" is an alkylene group of 1 to 4 carbon atoms;R'", R"" and R^(v) are each independently selected from a groupconsisting of alkyl radicals of 1 to 18 carbon atoms, --CH₂ C₆ H₅, --CH₂CH₂ OH, --CH₂ OH, and --(CH₂)_(x) NHC(O)R^(vi), wherein x has a value offrom 2 to 10 and R^(vi) is a perfluoroalkyl radical having from 1 to 12carbon atoms; X is chloride, bromide, fluoride, iodide, acetate ortosylate,the salt being aluminum-zirconium tetrachlorohydrexglycinatepowder.